The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 29, 1998
Filed:
Mar. 13, 1997
Shinichi Yamagishi, Hyogo, JP;
Noritaka Egami, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A demodulating method wherein the signal can be demodulated accurately even if the S/N ratio is lower by calculating an amplitude peak value by a specific formula from two values of an amplitude of an acoustic signal corresponding to a phase difference of 90 degrees at a carrier frequency transmitted by an acoustic signal transmitter, setting a threshold level preliminarily for the amplitude peak value, and demodulating the amplitude peak value by binarization on the basis of the threshold level, and a demodulating circuit and a demodulating apparatus used in the execution thereof. It is further possible to follow up automatically even when the acoustic characteristics change by automatically calculating the average of peak values of output of the vibration sensor in a state not transmitting the acoustic signal, automatically setting the signal level by a formula predetermined on the basis of the obtained average, and automatically calculating the threshold level from the average of the peak values and the signal level.